Did dinosaurs have any relation with dung‐beetles? (The origin of coprophagy)

Abstract

It is widely accepted that Mesozoic ecosystems were basically similar to Cenozoic ecosystems and it has been proposed that the role of dung-beetles in those ecosystems was identical to that of today, but the dung of dinosaurs were used as a source of food instead of the dung of mammals. While dinosaurs have been known since Triassic, Scarabeids are present in the fossil records probably since Lower Jurassic. But a very important metabolic feature of dinosaurs has not been taken into account, the connection between digestive and uro-genital systems. So here we propose the hypothesis that coprophagy in dung-beetles has been associated, since it began, with mammals.

If Dung Beetles (Scarabaeidae: Scarabaeinae) Arose in Association with Dinosaurs, Did They Also Suffer a Mass Co-Extinction at the K-Pg Boundary?

“…Trace fossils within herbivorous dinosaur coprolites attributed to tunneling dung beetles appear in the Upper Cretaceous, the oldest from the Campanian [ 72 , 76 ], younger than the oldest Scarabaeinae fossil ( Prionocephale deplanate Lin)[ 33 ]. Conversely, it has been argued that the mixing of uric acid with feces common to all non-mammals would have made dinosaur dung unsuitable [ 77 ], a hypothesis supported by the rarity of extant dung beetles utilizing reptile or avian dung. Molecular-clock based estimates for the crown age of marsupials and placental mammals are as old as 82 and 101Ma, with peak mammal diversification between 75-85Ma [ 78 ].…”

Biogeography of Aphodiinae dung beetles based on the regional composition and distribution patterns of genera

“…These ancestral lineages of Aphodiinae possibly had different feeding (mycetophagy or saprophagy; Scholtz & Chown, 1995) and ecological habits (forest‐ or sand‐dwellers), as has been observed previously within earlier branches of Iberian Aphodiinae, which show proportionally more of these tendencies than more recent groups (Cabrero‐Sañudo & Zardoya, 2004; Cabrero‐Sañudo, 2007). Although there are no fossil records for Aphodiinae from this period (Krell, 2003), the radiation of coprophagous beetles presumably happened as a response to an increasing rate of dung production, density and size of vertebrate droppings from dinosaurs and/or small mammals (Jeannel, 1942; Halffter & Matthews, 1966; Davis, 1990; Arillo & Ortuño, 2008), as is thought to have happened in the case of the sister group Scarabaeinae (Davis et al. , 2002).…”

Cockroaches Probably Cleaned Up after Dinosaurs

“…Probably an important feature of dinosaur and pterosaur excrements (as in birds and reptiles when compared with mammals) was the large proportion of nitrogen compared with phosphorus [16] . The association with urine and thus with a high concentration of phosphoric acid, oxalic and carbonic acids and salts, primarily sodium chloride, leads to the recent conclusion about the association of dung-beetles and coprophagy with mammals (not with dinosaurs) since the very beginning [17] . On the other hand, some common (11 of the 15 deposits) fossilised dinosaur coprolites contain 13–85% of rotting conifer wood with only 0.20–0.30% of nitrogen (conifers are utilized by the living cockroach Cryptocercus – the most important wood-decomposing cockroach) with its attendant microbial and detritivore fauna and thus augmented the resource options of Cretaceous ecosystems that lacked fodder provided by grasses and other derived angiosperms [8] , [18] .…”